NEOROCKS color survey: Final results

¹ IMCCE, Observatoire de Paris, CNRS UMRO 8028, PSL Research University, 77 av Denfert Rochereau, 75014 Paris Cedex, France
² Astronomical Institute of the Romanian Academy, 5 Cutitul de Argint, 040557, sector 4, Bucharest, Romania
³ LESIA, Université Paris Cité, Observatoire de Paris, Université PSL, Sorbonne Université, CNRS, 92190 Meudon, France
⁴ Institute of Astronomy, V. N. Karazin Kharkiv National University, 4 Svobody Sq., Kharkiv 61022, Ukraine
⁵ Institut Universitaire de France (IUF), 1 rue Descartes, 75231 Paris Cedex 05, France
⁶ INAF — Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monte Porzio Catone, Italy

Received: 24 April 2024
Accepted: 29 July 2024

Abstract

Context. Near-Earth objects (NEOs) are the most accessible small Solar System bodies by both spacecrafts and ground-based telescopes. Close encounters of these objects with Earth represent opportunities to characterize their physical and mineralogical properties. They are also a constant threat to humanity due to possible impact events with Earth. In this context, the NEOROCKS project has been financed by the European Union’s Horizon 2020 research and innovation program.

Aims. We present the final results on photometry of the NEOROCKS project, with the aim of extending the dataset of surface colors for small NEOs with unknown properties and, when possible, characterizing newly discovered NEOs.

Methods. Photometric observations were performed using the 1.2 m telescope at the Haute-Provence observatory (in France) in the BVRI filters of the Johnson-Cousins photometric systems between May 2022 and June 2023. The stability and dynamics of objects from the NEOROCKS database was investigated by numerical integration.

Results. We obtained new surface colors for 83 NEOs. Overall, the NEOROCKS color database contains 170 objects. The majority of the objects in the dataset with diameters D<500 m belong to a group of silicate bodies. We estimated the unbalanced percentage between S- and C-type objects as an observational bias due to reflective proprieties of the surface of objects. The average of Lyapunov time of about 100 years is evidence of highly chaotic orbits of objects from the color database of NEOROCKS. Asteroid 2011 OL51 has a reasonable probability of being a parent body contributor to the October Capricornidis meteor shower. Asteroids 2004 HK33, 2022 VV (D-type), 2003 WR21, and 2017 SE1 (A-type) belong to end-member classes and have ΔV<7 km/s; thus, they are possible candidates for in situ investigations.